Monitoring and operation of a liquid flow circuit containing a chemical additive

ABSTRACT

In a heat transfer system ( 10 ) including a liquid flow circuit ( 14 ) within which a liquid containing a chemical additive is circulated to flow through one or more transfer devices ( 11, 12 ) the circuit is provided with a sensor ( 17 ) operable to provide an output signal in the event of liquid flow into the liquid flow circuit.

This invention relates to the monitoring and operation of a liquid flowcircuit, such as the closed circuit of a central heating or coolingsystem, in which the circulated liquid, typically water or a water-basedliquid, contains a chemical additive such as an additive selected toinhibit corrosion within the system and or the formation of scaledeposits which potentially would reduce the efficiency of the system.

Additionally the invention may comprise monitoring and operation of aliquid flow circuit, and commissioning of a liquid flow circuit, inwhich a cleaning fluid or fluid for a flushing procedure is circulatedthrough the liquid flow circuit. Thus the present invention encompassesthe monitoring and operation of a liquid flow circuit when that circuitcontains a flushing fluid or a temporary chemical additive, such as maybe employed for cleaning, or a substantially permanent additive providedto inhibit corrosion.

Thus the liquid flow circuit may be that of a system which comprises aheat source such as a boiler and one or more heat emitting units such asradiators, or which is a cooling system comprising one or more heatextraction units.

A feature of closed circuit type heating and cooling systems is that itis necessary to fully or partially drain the system in the event of asystem component, such as a central heating boiler, a radiator or heatextraction unit needing to be removed or replaced.

A problem which then arises is that often the system is re-filled ortopped up only with water and lost inhibitor is not replaced. Thus thesystem is then operated without any inhibitor in the case of a systemthat has been fully drained, or with only an excessively dilutedsolution in the case of a system which has been partially drained. Ineither case the system components are then exposed to a heightened riskof corrosion and or scale formation.

The present invention seeks to provide a method and apparatus whichaddresses and seeks to overcome or mitigate the aforedescribed problemassociated with a heating or cooling system (hereinafter referred to asa heat transfer system) of the type which comprises a liquid flowcircuit of the kind which is intended to operate with a chemicaladditive such as an inhibitor.

In accordance with one aspect of the present invention there is provideda heat transfer system comprising a liquid flow circuit within which aliquid containing a chemical additive is circulated to flow through oneor more heat transfer devices, said circuit comprising a sensor operableto provide an output signal in the event of a liquid flow into theliquid flow circuit.

In accordance with another aspect of the present invention there isprovided a method of operation of a heat transfer system of the typecomprising a liquid flow circuit within which there is circulated aliquid containing a chemical additive, said method comprising providingthe system with a sensor which is operable to provide an output signalin the event of a liquid flow into the liquid flow circuit.

The system and method of the present invention is particularlyapplicable to the heat transfer system of a building or other spatiallyfixed environment. It is particularly directed to a system and methodwherein the system may be permanently or substantially permanentlyconnected to a supply of liquid for filling and/or topping up of thesystem. The system may be permanently or substantially permanentlyconnected to a supply of pressurised liquid for filling and or toppingup of the system in a manner in which filling and/or topping up occursautomatically, or, alternatively, manual means, such as a manuallyoperated valve or connection may be provided for manual control ofadmission of filling and/or topping up liquid to the liquid flowcircuit.

Preferably the sensor is operable to provide an output signal which is afunction of the volume of liquid flow into the liquid flow circuit.

The sensor, and a display, may be part of a monitoring device comprisingalso a data store to store information relating to the volume of liquidintroduced into an empty liquid flow circuit during initialcommissioning of the heat transfer system. The monitoring device may bepre-programmed to store information regarding an acceptableconcentration of the chemical additive and to display the requiredquantity of chemical additive that should be introduced into the systemfollowing initial filling of the system in order to achieve anacceptable concentration of additive.

A volume flow display may be associated with the sensor for displayingthe volume of liquid, typically water, which has entered the liquid flowcircuit, for example during initial filling of the liquid flow circuitwhen commissioning the system, or during a subsequent topping up of thesystem, whereby said volume information may be employed to enable acorrect amount of chemical additive to be introduced into the liquidflow circuit to provide an acceptable concentration of chemical additivewithin the liquid flow circuit.

The sensor may have associated therewith re-set means whereby followingaddition of chemical additive to the liquid flow circuit the display maybe re-set, e.g. zeroed, thereby to display only the volume of liquidentering the liquid flow circuit subsequent to an addition of chemicaladditive.

The chemical additive may be introduced into the liquid flow circuit ata position upstream of the sensor whereby, particularly in the case of aliquid chemical additive introduced into a water filled circuit, thesensor may detect flow of water into the circuit and also flow of liquidchemical additive. Alternatively, however, the chemical additive may beintroduced into the liquid flow circuit at a position downstream of thesensor whereby, particularly in the case of a liquid chemical additiveintroduced into a water-filled circuit, the sensor detects only the flowof water into the circuit and not the flow of liquid chemical additive.

A monitoring device comprising the sensor may be in communication with,or adapted for communication with a dosing device which is operable tointroduce chemical additive into the liquid flow circuit. The monitoringdevice may be operable to provide information to the dosing devicerelating to the required quantity of chemical additive to be introducedinto the liquid flow circuit and/or the monitoring device may beoperable to receive information from the dosing device in respect of thequantity of chemical additive that has been introduced into the liquidflow circuit. The dosing device may be operable automatically tointroduce chemical additive into the liquid flow circuit in response toa signal from the monitoring device or it may be manually operable.

The dosing device may incorporate or be responsive to software which issubstantially integral with that of the monitoring device.

The monitoring device may be operable to guide an operator throughperforming a set of sequential actions necessary to result in correctcommissioning or re-filling of a heating or cooling system. It may, forexample, require the sequential operations of draining and/or fillingthe liquid flow circuit, adding a correct amount of cleaning fluid,circulating the cleaning fluid, draining, flushing, re-filling and thenadding a correct amount of chemical inhibitor, or require at least twoor more of said operational steps.

The monitoring device may comprise a data store which records a historyof operation undertaken in respect of flow of liquid, such as water,into the liquid flow circuit, and/or introduction of chemical additive.If the dosing device is not in direct communication with the monitoringdevice, the monitoring device may comprise a data input facility wherebyinformation may be entered manually in respect of the quantity ofchemical additive which has been introduced into the liquid flowcircuit.

In the specification of our UK patent GB 2462518 there is described inrelation to in-line testing for inhibitor concentration procedural stepsfor guiding or controlling operations required during a commissioningprocedure. Similar procedural steps may be employed in the context ofthe present invention but involving the detecting of flow volumesinstead of the technique described in GB 2462518 of employing tracerchemicals.

Following initial commissioning of a heat transfer system the sensor maybe employed to monitor small additions of water to the liquid flowcircuit and to provide a signal indicative of a requirement for chemicalinhibitor addition when cumulative losses of liquid (whether water orinhibitor) have reached a pre-defined level. When that pre-defined levelis reached the system, for example a monitoring device, may provide analarm signal to indicate the need for the introduction of chemicalinhibitor or a dosing device may be caused automatically to introduceadditional chemical inhibitor into the liquid flow circuit. Preferablythe system is operable to determine the top-up quantity of chemicaladditive that requires to be introduced into the liquid flow circuit andeither to display that quantity or automatically cause operation of adosing device to introduce that quantity of chemical additive into theliquid flow circuit.

Particularly but not exclusively in the case of automatic operation of adosing device preferably an alarm function is provided whereby a visualor audible alarm is generated in the event of the dosing device notcontaining any, or containing only insufficient chemical additive neededto restore the concentration of additive to the required level ofconcentration.

The heat transfer system may comprise a monitoring device which monitorsthe rate of addition of system water or other liquid (and thus byinference the rate of water lost) per unit time thereby to identify apersistent leak of fluid from the system and to raise an alarm signalwhich may be independent from any other programmed alarm systems andsettings. The system may comprise means operable automatically ormanually in response to an alarm signal for introduction of a leaksealing chemical into the liquid flow circuit.

The heat transfer system additionally may comprise a pressure monitorwhich is operable to initiate an alarm signal in the event of asignificant loss of pressure which is indicative of a malfunction. Theheat transfer system may comprise a valve operable to inhibitintroduction of water or other liquid, or chemical additive into thesystem in the event of a substantial drop of pressure which isindicative of a major loss of liquid from the system.

Examples of alarm and other functions which may be incorporated into theheat transfer system include:—

-   -   After filling, but before addition of inhibitor, a status alarm        on a monitoring device, such as a red LED, may be displayed, and        arranged to turn green, or some other colour when the correct        amount of inhibitor has been added.    -   A monitoring device may provide a display or other form of alarm        when chemical inhibitor needs to be added to the system, and        preferably the monitoring device displays the measured system        volume as determined during initial commissioning thereby to        allow an operator or householder to calculate manually and add        the correct amount of inhibitor. A monitoring device may enable        the calculated amount of inhibitor to be entered and then        confirmed by the monitoring device as being correct, or        alternatively the monitoring device may display the required        quantity of inhibitor to be added to the system.    -   The system water treatment history may be displayed directly on        a display associated with a monitoring device or on another        device which is physically or electronically associated with the        sensor and an alarm may be generated in the event of any        detected malfunction.    -   Remote monitoring whereby the alarm state information is        transmitted to a remote observer via one or more of known types        of communication protocols such as WiFi or the Internet. The        alarm state information may be integrated into other software        solutions to trigger rectifying actions, for example        automatically to initiate attendance of a service engineer.    -   The system may comprise a monitoring device which displays the        water treatment history thereby to allow the householder or        service provider to undertake their own diagnosis or follow        suggested rectification actions following operation of an alarm.    -   The system may comprise a monitoring device which is in        communication with a central heating boiler to prompt required        action from the boiler, for example to prompt operation of a        circulation pump, provided integrally with the boiler, at the        time of or following addition of a cleaner or inhibitor to the        liquid flow circuit.    -   The output signal may be in the form of a warning signal which        acts as an alarm, whether visual or audible, to alert a user to        the need to replenish the system with chemical additive, for        example a liquid chemical additive such as a liquid inhibitor.    -   The system may comprise a monitoring device which is in        communication with a central heating boiler to cause either        shutting down of the boiler or reduction of the heat output of        the boiler in the event that any required maintenance or other        corrective action has not been undertaken, for example within a        prescribed time period.

The heat transfer system may be of the type comprising a closed circuitcontaining liquid at above atmospheric pressure, or it may be of anopen, unpressurised type.

The dosing device, irrespective of whether it is responsive to an outputsignal from the sensor, may be of a type which interacts with the sensorto cause re-setting of the sensor and an alarm function followingoperation of the dosing device to inject replenishment chemical into thesystem.

The dosing device may be of a kind comprising the combination of aninlet port in fluid communication with the liquid flow circuit and acontainer of replenishment chemical secured to or adapted to be securedto the inlet port.

Preferably the inlet port has a specific, preferably unique, profilewhich enables it to receive replenishment chemical only from a containerhaving a profile complementary to that of the inlet port. Thus if asupplier of replenishment chemical ensures that only one specific typeor range of replenishment chemical is supplied in containers having aspecific profile which is uniquely associated with that replenishmentchemical, it is possible to ensure that a container can introduce intothe liquid flow circuit only a replenishment chemical which is the sameas or compatible with chemical previously introduced into the circuitvia said inlet port.

Alternatively or additionally to a container and inlet port havingcomplementary profiles which are uniquely associated with a type ofchemical or range of chemicals, the container may incorporatecommunication means to recognise and respond to a signal from themonitoring device and thereby allow the monitoring device to cease togenerate a continued warning signal and be re-set. That is, if acontainer is employed which has not necessarily been filled with asuitable type of replenishment chemical, the monitoring device maycontinue to provide a warning signal until an appropriate container hasbeen employed and the sensor re-set.

The sensor for measuring the volume of flow of liquid, such as water,into the liquid flow circuit may be operable continually to monitor forflow of liquid or it may operate intermittently. The sensor may beoperable normally at a low frequency, such as once per minute, but thento automatically switch to a higher or progressively increasingfrequency of sampling if, when in the low frequency sampling but thenautomatically switch to a higher or progressively increasing frequencyof monitoring if a flow is detected. The sensor may be mains powered,battery powered or of a type operable from wither a battery or mainssupply.

Embodiments of the present invention will now be described, by way ofexample only, with reference to the accompanying diagrammatic drawingsin which:—

FIG. 1 is a schematic view of a central heating system in accordancewith the present invention, and

FIG. 2 shows diagrammatically a commissioning protocol which may beemployed for the central heating system of FIG. 1.

A domestic central heating system 10 comprises a condensing boiler heatexchanger 11, two radiators 12 located at first floor level and tworadiators 13 at ground floor level, said radiators and boiler beinginter-connected in a closed loop pressurised circuit by pipe work 14. Avalve 15 facilitates drainage of the system and a pressurised dosingdevice 18 facilitates addition of corrosion and lime scale inhibitorinto the water contained within the circuit.

In proximity to the heat exchanger 11 there is a supply pipe 16 which issubstantially permanently connected to a mains water supply and, via apressure control valve 22 facilitates flow of water into the pipe work14 of the liquid flow circuit of the system 10. Fitted to that pipe 16is a T connector which houses a volume flow sensor 17 which is operableto measure the volume flow of water through the pipe 16. The volume flowsensor 17 is positioned downstream of the position at which the dosingdevice introduces inhibitor for the liquid flow circuit.

Associated with the sensor 17 is a display 19 which provides a visualdisplay of the volume of water that has flowed through the pipe 16. Thesensor and display form part of a management device that also comprisesa data store and processing function whereby, in use, the volume flowinformation may be used to calculate the quantity of a chemicaladditive, whether a cleaning additive or inhibitor, that should be addedto the water in the pipe work 14 via the dosing device 18. The requiredquantity is then indicated on the display 19.

The heat exchanger 11, the volume flow sensor 17 and the dosing devicein the example of this embodiment of the invention are all providedintegrally within a boiler casing 21.

In this embodiment of the invention the display 19 facilitates manualoperation of the dosing device for introduction of cleaning fluid orinhibitor. However it is to be understood that the central heatingsystem may be modified to incorporate one or more of the optionsaforedescribed, for example automatic operation of the dosing device viaa connection 24 in response to a signal from a monitoring devicecomprising said sensor 17 and display 19, and/or provision of alarmsignals also as aforedescribed, and/or automatic introduction of a leaksealer chemical or alarm to alert to the need for manual introduction ofa leak sealer chemical.

Optionally the feed pipe 16 may incorporate a shut off valve 23 whichoperates automatically to prevent further flow of water into the pipework 14 in the event that the sensor 17 has detected a high volume offlow at a time other than initial commissioning or flushing or cleaningof the system, and which therefore is indicative of a significantleakage or drainage of liquid from the pipe work 14.

Optionally the system may incorporate, as a check on the concentrationof chemical additive in the system, an on-line monitoring device such asthat the subject of our UK patent GB 2462518.

Whether for a central heating or cooling system the sensor 17 anddisplay 19 may be part of a monitoring device which guides an operatorthrough performing a set of sequential actions to ensure correctcommissioning of the system. An example of a suitable softwarealgorithm, in particular one for a system which expects chemicals of aparticular identity to be introduced into the liquid flow circuit, isshown in FIG. 2. The display is operable to indicate any one of fourdifferent fault situations and also comprises two display positions,position A and position B which indicate respectively whether there isinsufficient or sufficient inhibitor in the system. The fault 1 displayis indicative of the inhibitor level being lower than the minimumrequired, fault 2 is indicative of a cleaner fluid not having beenflushed, fault 3 is indicative of cleaner fluid having beeninsufficiently flushed and fault 4 is indicative of the cleaner nothaving been circulated through the system for sufficient time.

Accordingly by provision of a monitoring device which provides theaforementioned information the operator is guided through the correctcommissioning procedure and the risk of incorrect or incompletecommissioning is reduced.

Although the invention has been described in relation to a domesticcentral heating system it may be employed also in respect of a coolingsystem.

Having regard to the foregoing it will be understood that the presentinvention facilitates a more reliable and accurate operation of a heattransfer system and which more readily facilitates introduction ofadditional top up chemical additive as and when required.

1-15. (canceled)
 16. A heat transfer system comprising a liquid flowcircuit within which a liquid containing a chemical additive iscirculated to flow through one or more heat transfer devices, saidcircuit comprising a sensor operable to provide an output signal in theevent of a liquid flow into the liquid flow circuit subsequent toinitial filling of the liquid flow circuit
 17. A system according toclaim 16 and adapted for permanent or substantially permanent connectionto a supply of liquid for flow into the liquid flow circuit.
 18. Asystem according to claim 16 wherein the sensor is operable to providean output signal which is a function of the volume of liquid flow intothe liquid flow circuit.
 19. A system according to claim 16 andcomprising a volume flow display to display the volume of liquid whichhas entered the liquid flow circuit.
 20. A system according to claim 19wherein the display has associated therewith re-set means wherebyfollowing addition of liquid or chemical additive to the liquid flowcircuit the display may be re-set thereby to display only the volume ofliquid subsequently entering the liquid flow circuit.
 21. A systemaccording to claim 19 wherein said sensor and display are part of amonitoring device comprising also a data store to store informationrelating to the volume of liquid introduced into the liquid flow circuitduring initial commissioning thereof.
 22. A system according to claim 21wherein the sensor is in communication with, or adapted forcommunication with a dosing device which is operable to introducechemical additive into the liquid flow circuit.
 23. A system accordingto claim 22 wherein the dosing device is operable automatically tointroduce chemical additive into the liquid flow circuit in response toa signal from the monitoring device.
 24. A system according to claim 21wherein the monitoring device is operable to guide an operator throughperforming a set of sequential actions necessary to result in correctcommissioning or re-filling of a heating or cooling system.
 25. A systemaccording to claim 21 wherein the monitoring device comprises a datastore operable to record a history of operations undertaken in respectof flow of liquid into the liquid flow circuit and/or introduction ofchemical additive.
 26. A system according to claim 21 wherein themonitoring device is operable to monitor the rate of addition of liquidinto the liquid flow circuit per unit time thereby to identify apersistent leak of fluid from the system.
 27. A system according toclaim 16 wherein the sensor is in communication with or adapted forcommunication with a dosing device, wherein the dosing device isoperable automatically to introduce required chemical additive into theliquid flow circuit and wherein an alarm is generated in the event ofthe dosing device not containing any or containing only insufficientchemical additive needed to restore the concentration of additive to therequired level of concentration.
 28. A system according to claim 16 andcomprising a pressure monitor operable to initiate an alarm signal inthe event of a significant loss of pressure in the liquid flow circuit.29. A system according to claim 16 wherein the sensor is operable toprovide an output signal which is a function of the volume of liquidentering the liquid flow circuit subsequent to initial filling of theliquid flow circuit.
 30. A method of operation of a heat transfer systemof the type comprising a liquid flow circuit within which there iscirculated a liquid containing a chemical additive, said methodcomprising providing the system with a sensor which is operable toprovide an output signal in the event of a liquid flow into the liquidflow circuit subsequent to initial filling of the liquid flow circuit31. A system according to claim 30 wherein the sensor is operable toprovide an output signal which is a function of the volume of liquidentering the liquid flow circuit subsequent to initial filling of theliquid flow circuit.